Kinetically modified parametric instabilities of circularly polarized Alfvén waves: Ion kinetic effects
Kinetically modified parametric instabilities of circularly polarized Alfvén waves: Ion kinetic effects
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DOI：
10.1063/1.2399468
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发表时间：
2006-08
影响因子：
2.2
通讯作者：
Y. Nariyuki;T. Hada
中科院分区：
文献类型：
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作者：
Y. Nariyuki;T. Hada
在离子和无质量电子流体的一维Vlasov描述框架下，研究了均匀背景等离子体中平行传播的有限振幅圆极化Alfven波的参数不稳定性，从而考虑了纵向的动力学扰动(离子朗道衰减)。目前的表述还包括霍尔效应。所得结果与以往的相关分析结果吻合较好，表明在Alfven波的参数不稳定性中，纵向的动力效应起着主要作用，而动力效应是被动反应的。此外，对于具有小波数子波的区域，证实了动力学参数不稳定性的存在。这些不稳定性的增长速率对离子温度很敏感。文中给出的公式和结果可应用于太阳风和地球前震地区观测到的阿尔芬波。
Parametric instabilities of parallel propagating, circularly polarized, finite amplitude Alfven waves in a uniform background plasma is studied, within a framework of one-dimensional Vlasov description for ions and massless electron fluid, so that kinetic perturbations in the longitudinal direction (ion Landau damping) are included. The present formulation also includes the Hall effect. The obtained results agree well with relevant analysis in the past, suggesting that kinetic effects in the longitudinal direction play essential roles in the parametric instabilities of Alfven waves when the kinetic effects react “passively.” Furthermore, existence of the kinetic parametric instabilities is confirmed for the regime with small-wave-number daughter waves. Growth rates of these instabilities are sensitive to ion temperature. The formulation and results demonstrated here can be applied to Alfven waves observed in the solar wind and in the earth’s foreshock region.